Dam safety, navigability, restoration and removal projects

 

All over the country rivers and streams have low-head dams and diversion structures.  While some still serve important functions for communities, utility companies or irrigators, many are obsolete while some still serve important functions for communities, utility companies or irrigators.  Often these dams create a significant hazard for recreational river users. Dams account for a number of accidental drownings in the US every year.  Many communities are looking at ways to either safely remove or safely replace these deteriorating dams.  Recreation Engineering and Planning specializes in turning these unsightly hazards into recreational amenities.  Our company has worked on two types of dam removal projects.  In some cases the existing low head dam is enhanced while additional structures are added downstream to “step down” the head over a series of smaller drops.  In this case the existing dam structure remains and serves its design function—the difference is that what was often a single deadly drop is now a series of safer, more enjoyable whitewater rapids.  This type of dam removal can turn a hazard in the midst of a community into the type of tourist attraction that significantly affects the local economy.  One example of this type of project is the Pueblo Whitewater Park, which steps down over 14 feet of head in eight separate drop structures.  During this reconstruction, the existing crest of the dam was maintained as were the existing upstream water surface elevation and the existing rating curve.  The subsequent drops created a pool and drop whitewater park that extends over 1000 feet downstream.  The structures, which span a river that is approximately 230 feet wide, create some of Colorado's best surfing opportunities and have helped the Pueblo Whitewater Park to become host to a major festival and to experience extensive usage by locals and visitors alike.  Pictures of the park are shown below.  There is also a project sheet shown in the links to the left.  Total construction cost for this project was approximately $1 million.

Another similar project was completed in record time on the San Marcos River in San Marcos, Texas.  Recreation Engineering and Planning was asked to look at a failed dam that had been used for tubing as part of the fund raising efforts of the local Lions Club.  Recreation Engineering and Planning proposed a plan that extended the recreational usage area of the river by creating three drops where only a single drop had existed before, and removed failed walls on the river bank, grading the bank down to the river for easier user and spectator access.  Previous estimates for the rebuilding of the dam were in the neighborhood of $1.6 million.  Recreation Engineering and Planning implemented this design for less than $.5 million.  The improvements were a dramatic success.  The park has seen unrivaled usage since its completion, and Recreation Engineering and Planning has since been asked to advise several projects in the surrounding area.

An unparalleled project of this type is being planned for the Calgary Weir in Calgary, Alberta.  This dam crest has a drop of 12 feet and a width that exceeds 700 feet.  Total flood flows at this site are in the hundreds of thousands of cubic feet per second.  This is a tremendously high volume river and Recreation Engineering and Planning's multiple channel design will allow for beginner boat passage as well as world class surfing and play-boating.  Recreation Engineering and Planning has worked with Golder Engineering and Northwest Hydraulics to complete the computer and physical modeling for the channels.  Pictures shown below are from the modeling project done at Pacific Hydraulics Labs in Alberta.  Construction is scheduled to begin next year.

Recreation Engineering and Planning also excels in complete dam removal and riverbed restoration.  These restorations feature pool, drop and riffle structures for in-stream habitat, a restored riparian zone, and a natural sanctuary for the local community and visitors alike to revel in a stunning natural setting with stream-side trails, river access points and unmatched whitewater features.  Our drop structures serve to stabilize the river bed and produce natural drop, scour pool and riffle morphology that leads to a healthy and natural streambed conducive to riparian zone restoration and in-stream habitat restoration.  This type of dam removal has been implemented in many locations, including our downtown Reno Whitewater Park.